14th July 2017, 22:04 Edited(This post was last modified: 18th July 2017, 20:09 by Jett_.)

FreeCAD is probably the best general purpose free open source 3D modeling program for Linux.
Their website is https://freecadweb.org/.
It is probably in the repos too.
The current release is FreeCAD v. 0.16 and the current development version is the 0.17 and it works well and has newer features.
LibreCAD is a nice free open source 2D CAD application for Linux. It was forked from the community version of QCAD.
It works very well.
Their website is http://librecad.org/cms/home.html